What Is Bitcoin (BTC)? The Plain-English Explainer

Bitcoin is the first cryptocurrency that worked at scale. It was described in a nine-page whitepaper published in 2008 by the pseudonymous Satoshi Nakamoto, and the network went live on 3 January 2009. The core idea: money that can be sent directly between two people over the internet, without a bank or payment company in the middle.

How does Bitcoin actually work?

All transactions are recorded on a public ledger called the blockchain — a chain of blocks, each containing a batch of transactions. Roughly every 10 minutes, miners compete to add the next block by solving a computational puzzle (proof-of-work). The winner earns newly issued bitcoin plus the transaction fees in that block. Because changing history would require redoing all the work of every later block, the ledger is practically tamper-proof.

• No central issuer: rules are enforced by tens of thousands of independent nodes.
• Transparent: every transaction since 2009 is publicly auditable.
• Self-custody possible: whoever holds the private keys controls the coins — no account can be frozen by a third party.

Why only 21 million coins?

The issuance schedule is hard-coded: new supply is cut in half every 210,000 blocks (roughly four years) in an event called the halving. This makes Bitcoin provably scarce — unlike national currencies, nobody can print more. See our halving explainer for the full schedule and what it means for miners.

What is a satoshi?

You do not need to buy a whole bitcoin. Each BTC divides into 100,000,000 satoshis ("sats"), so $10 buys you a small fraction of a coin. Use the converter to see exactly how much BTC any amount of USD, CNY or EUR gets you at the live rate.

What moves the price?

• Supply and demand on exchanges — the immediate driver of every tick.
• Halving cycles, which reduce new supply roughly every four years.
• Macro liquidity: interest rates and risk appetite move Bitcoin like other risk assets.
• Institutional flows, including spot ETF inflows and outflows.
• Regulatory news in major markets.

Bitcoin is volatile — double-digit swings in a week are normal. Never invest money you cannot afford to lose, and consider spreading entries over time (see our DCA guide).